NILE CANALS—DIVERSION OF RIVERS. 499 
structed to water that basin, to regulate the level of Lake 
Moeris, and possibly, also, to diminish the dangers resulting 
from excessive inundations of the Nile, by serving as waste-weirs 
to discharge a part of its overflowing waters.* Several of the 
seyen ancient mouths of the Nile are believed to be artificial 
channels, and Herodotus even asserts that King Menes diverted 
the entire course of that river from the Libyan to the Arabian 
side of the valley. There are traces of an ancient river-bed 
along the western mountains, which give some countenance to 
this statement. But it is much more probable that the works 
of Menes were designed rather to prevent a natural, than to 
produce an artificial, change in the channel of the river. 
Two of the most celebrated cascades in Europe, those of the 
Teverone at Tivoli and of the Velino at Terni, owe, if not their 
existence, at least their position and character, to the diversion 
vf their waters from their natural beds into new channels, in 
order to obviate the evils produced by their frequent floods. 
Remarkable works of the same sort have been executed in 
Switzerland, in very recent times. Until the year 1714, the 
Kander, which drains several large Alpine valleys, ran, for a 
considerable distance, parallel with the Lake of Thun, and a 
few miles below the city of that name emptied into the river 
Aar. It frequently flooded the flats along the lower part of its 
course, and it was determined to divert it into the Lake of Thun. 
For this purpose, two parallel tunnels were cut through the in- 
tervening rock, and the river turned into them. ‘The violence 
of the current burst up the roof of the tunnels, and, in a very 
short time, wore the new channel down not less than one hun- 
dred feet, and even deepened the former bed at least fifty feet, 
for a distance of two or three miles above the tunnel. The 
lake was two hundred feet deep at the point where the river 
was conducted into it, but the gravel and sand carried down by 
* The starting-points of these anals were far up the Nile, and of course ata 
comparatively high level, and it is probable that they received water only 
during the inundation. Linant Bey calculates the capacity of Lake Moeris at 
3,686,667 cubic yards and the water received by it at high Nile at 465 cubic 
yards the second, 
